Statement of the Technical Field
The present invention is in the technical field of digital communications. More particularly, methods and systems for fast data acquisition and synchronization of transmitters and receivers.
Description of the Related Art
In digital communication systems, the performance of synchronization processing during demodulation and data recovery from received signal has become an important issue. In general digital communication systems, a transmitter sends digital information synchronized with a remote clock. A receiver recovers the transmitted signal by sampling with a local clock. Since the remote clock and local clock are from different sources, a synchronization process should be performed at the receiver for proper demodulation of the transmitted signal. Synchronization is implemented by adjusting a fractional time delay between a remote clock and a local clock. In other words, the sampling phase of a local clock is adjusted to achieve the maximum eye opening (i.e. minimal signal distortion).
This synchronization process is necessary for all digital communication systems, but requires complex hardware and substantial processing time to achieve reliable performance. Also, a sampling clock should be synchronized to a received signal for the entire communication period during which a signal is received. For initial synchronization and to maintain symbol synchronization, a preamble is typically inserted at the beginning of a frame. It is periodically repeated until the end of communication.
In some applications such as radio frequency identification (RFID), near field communication (NFC), and sensor networks, for example, the amount of data to be transferred between a transmitter and a receiver is relatively small. This is particularly true in a wireless sensor networks, because synchronization time and data frame length determines the maximum number of nodes and/or a monitoring rate. Therefore, synchronization time is an important design factor.